Aortic heart valve prosthesis implantation tool

ABSTRACT

Improved tools for visualizing, sizing and/or marking include a prosthesis template with a diameter approximately equal to the diameter of an aortic heart valve prosthesis. In preferred embodiments, the prosthesis template has an annulus end and a sinotubular junction end wherein the diameter at the annulus end is less than the diameter at the sinotubular junction end. The prosthesis template can include a marking element configured to mark tissue at particular positions relative to the prosthesis template. Marking can be performed with a variety of techniques.

BACKGROUND OF THE INVENTION

[0001] The invention relates to tools that assist with the selection andattachment of aortic heart valve prostheses. In particular, theinvention relates to tools to help select a prosthesis with the correctsize and markers for marking the aortic tissue to guide placement andattachment of the prosthesis.

[0002] Prostheses, i.e., prosthetic devices, are used to repair orreplace damaged or diseased organs, tissues and other structures inhumans and animals. Prostheses must be generally biocompatible sincethey are typically implanted for extended periods of time. For example,prostheses can include artificial hearts, artificial heart valves,ligament repair material, vessel repair, surgical patches constructed ofmammalian tissue and the like.

[0003] Prostheses can be constructed from natural materials such astissue, synthetic materials or a combination thereof. For example,prostheses formed from purely synthetic materials, such as mechanicalheart valve prostheses, can be manufactured, for example, frombiocompatible metals, ceramics, carbon materials, such as graphite,polymers, such as polyester, and combinations thereof. Mechanical heartvalves can be manufactured with rigid occluders or leaflets that pivotto open and close the valve, or flexible leaflets that flex to open andclose the valve.

[0004] Although mechanical heart valves with rigid pivoting occludershave the advantage of proven durability through decades of use, they areassociated with blood clotting on or around the prosthetic valve. Bloodclotting can lead to acute or subacute closure of the valve orassociated blood vessel. For this reason, patients with implantedmechanical heart valves remain on anticoagulants for as long as thevalve remains implanted. Anticoagulants impart a 3-5% annual risk ofsignificant bleeding and cannot be taken safely by certain individuals.

[0005] Heart valve prostheses can be constructed with flexible tissueleaflets or polymer leaflets. Prosthetic tissue heart valves can bederived from, for example, porcine heart valves or manufactured fromother biological material such as bovine pericardium. Biologicalmaterials in prosthetic heart valves generally have profile and surfacecharacteristics that provide laminar, nonturbulent blood flow.Therefore, intravascular clotting is less likely to occur than withmechanical heart valves.

[0006] However, prosthetic tissue heart valves are limited by a tendencyto fail beginning about seven years following implantation.Calcification, i.e., the deposition of calcium salts, especially calciumphosphate (hydroxyapatite), appears to be a major cause of degeneration.Thus, tissue heart valves are generally used for older patients whoexperience less calcification and require the valve for shorter lengthsof time. In addition, various approaches have been developed to reducethe effects of calcification, such that tissue heart valves will havegreater durability. As these approaches achieve demonstrated long termeffectiveness, tissue heart valves likely will find greater use.

[0007] In a heart, blood flow between the respective atria andventricles and flow from the ventricles are controlled by heart valves.Blood flow from the right ventricle of the heart passes into thepulmonary artery. Blood flow from the left ventricle of the heart passesinto the aorta. Blood flow between the left ventricle and aorta passesthrough the aortic heart valve located near the connection of the aortawith the heart. The natural aortic heart valves has three leaflets thatopen to allow flow into the aorta and close to prevent back flow intothe left ventricle.

[0008] Tissue leaflets have sufficient flexibility to open and close.Each of the three leaflets of a natural valve are attached to thecylindrical wall of the aorta along a nonplanar curve. Coronary arteriesjoin the aorta near the valve. A commissure post can block or partiallyblock a coronary artery. This complicates the placement of a stentlessaortic prosthesis.

[0009] Attachment of a stentless aortic heart valve is complicated sincesuturing must be performed on both inflow and outflow edges of the valveto secure the valve. Significant pressures are exerted against the valvein use. Due to the pressures, it is desirable to suture the prostheticvalve along the commissure supports to ensure that the valve does notpull away from the aorta. That suturing along the commissure supports isdifficult because the valve is within the aorta during the implantation.

SUMMARY OF THE INVENTION

[0010] In a first aspect, the invention pertains to a tool including aprosthesis template. The prosthesis template has an annulus end and asinotubular junction end. The prosthesis template further includes aplurality of posts around the circumference extending toward thesinotubular junction end. In preferred embodiments, the diameter at theannulus end is less than the diameter at the sinotubular junction end.

[0011] In another aspect, the invention pertains to a tissue markingdevice including a prosthesis template having an annulus end and asinotubular junction end. A diameter of the annulus end is less than adiameter of the sinotubular junction end. The prosthesis templateincludes a marking element configured to mark tissue at particularpositions relative to the prosthesis template.

[0012] In a further aspect, the invention pertains to a tissue markingdevice including a prosthesis template having an annulus end and asinotubular junction end. A diameter of the annulus end is less than adiameter of the sinotubular junction end. The marker has a marking tipthat interfaces with notches of the prosthesis template. The marker isseparately positionable from the prosthesis template.

BRIEF DESCRIPTION OF THE DRAWINGS

[0013]FIG. 1 is a perspective view of a sizer/marker tool positionedwithin an aorta at its attachment to the heart, in which the aorta isdepicted as transparent for illustrative purposes to provide a view ofthe tool within the aorta.

[0014]FIG. 2 is a perspective view of a sizer/marker tool.

[0015]FIG. 3 is a perspective view of an aortic heart valve prosthesis.

[0016]FIG. 4A is a side view of an alternative embodiment of aprosthesis template.

[0017]FIG. 4B is a side view of another alternative view of a prosthesistemplate.

[0018]FIG. 5 is a side view of an embodiment of a sizer/marker with anannulus end with a smaller diameter than the diameter of the sinotubularjunction end.

[0019]FIG. 6 is a perspective view of a sizer/marker with a handledepicted as transparent for illustrative purposes to show a markingfluid. The insert shows the internal structure surrounding a pore inwhich the pore has a tip marking material.

[0020]FIG. 7 is a fragmentary view of the handle of the sizer/marker ofFIG. 6.

[0021]FIG. 8 is a cut-away view of the prosthesis template of thesizer/marker of FIG. 6, in which the surface of the template has beenremoved to expose internal structure.

[0022]FIG. 9 is a side view of an alternative embodiment of asizer/marker with a marking fluid, in which the handle is transparentfor illustrative purposes, such that internal structure can be observed.

[0023]FIG. 10 is a fragmentary side view of a prosthesis template and aportion of the handle, in which the prosthesis template has needles formarking.

[0024]FIG. 11 is a perspective view of a sizer/marker with cooling fluidfor marking, in which the handle is transparent for illustrativepurposes.

[0025]FIG. 12 is a perspective view of a transducer and associatedcomponents of a sizer/marker for marking using propagated energy, inwhich the outline of the handle is shown in phantom lines.

[0026]FIG. 13 ius a perspective view of a prosthesis template withposition indicators for use with a marker or suture needle.

[0027]FIG. 14 is a perspective view of a marker for use with theprosthesis template of FIG. 13.

[0028]FIG. 15 is a perspective view of a prosthesis template withposition indicators.

[0029]FIG. 16 is a top view of the prosthesis template of FIG. 15.

[0030]FIG. 17 is a front view of the prosthesis template of FIG. 15, inwhich a front view corresponds to looking toward extension 464.

[0031]FIG. 18 is a side view of the prosthesis template of FIG. 15.

[0032]FIG. 19 is a bottom view of the prosthesis template of FIG. 15.

[0033]FIG. 20 is a side view of an alternative embodiment of aprosthesis template.

[0034]FIG. 21 is another side view of the prosthesis template of FIG.20.

[0035]FIG. 22 is a perspective view of the prosthesis template of FIG.20.

[0036]FIG. 23 is a side view of a further embodiment of a prosthesistemplate.

DETAILED DESCRIPTION OF THE ILLUSTRATIVE EMBODIMENTS

[0037] A sizing and/or marking device can assist with size determinationand/or can guide the attachment of aortic heart valve prostheses,particularly stentless tissue-based prostheses. Use of the sizer/markertool can speed and simplify the valve replacement process. Thesizers/markers generally include a section with an outer surface havingsize and shape corresponding generally to the outer surface of an aorticheart valve prosthesis. This section has a generally cylindrical shapethat is roughly planar on one edge of the cylinder and has three postson the other edge corresponding to the commissure supports of an aorticvalve. In alternative embodiments, the sizer/marker is scalloped on oneend and has posts extending from the other end of the valve. In someembodiments, to conform to the shape of diseased valves, thesizer/marker is tapered outward from the annulus end, i.e., the inflowedge, toward the sinotubular junction end, i.e., the outflow edge. Thesizer/marker can also be similarly used in pulmonary valve replacementor other prosthetic heart valve replacement.

[0038] A set of the sizers/markers can be used such that a sizer/markerwith the correct size for the corresponding prosthesis can be selectedby placing the sizer/marker in position within the aorta at theconnection with the heart to evaluate the appropriateness of the size.The orientation and clearance of the coronary ostia can also beevaluated with the sizer/marker positioned within the aorta. To assistwith manipulation of the tool, a handle can be attached to the sectionof the sizer/marker that serves as a template for the prosthesis. Also,the device can include structures that can make marks such that theaorta can be marked at positions that indicate how to position theactual prosthesis and/or where to place the sutures. In someembodiments, the sizer/marker includes position indicators such that aseparate marking tool can make marks at positions indicated by theproperly oriented sizer/marker tool.

[0039] Damaged or diseased natural heart valves can be replaced torestore valve function. Heart valve prostheses can be purely mechanicalwith rigid occluders that pivot on hinges to open and close the valve toprovide generally one way flow. Alternatively, heart valve prosthesescan be tissue based in which appropriately treated tissue forms flexibleleaflets similar in structure to natural tissue leaflets and other partsof the valve. In particular, native heart valves can be harvested andformed into allograft or xenograft prostheses. Xenograft tissue isgenerally fixed prior to use. In other embodiments, tissue is formedinto a structure resembling natural leaflets. Similarly, flexiblesynthetic materials, especially polymers, can be formed into syntheticleaflets that function similarly to tissue leaflets. The patient can bean animal, especially a mammal, and preferably is a human.

[0040] The aortic valve is located between the left ventricle and theaorta. The end of the aortic valve proximal to the left ventricle isreferred to as the annulus end and the end of the aortic valve in theaorta proximal to the ostia is referred to as the sinotubular junctionend. Natural aortic valves have three leaflets, although heart valveprostheses can have a different number of leaflets. The aortic valvesare located near the location where the aorta connects to the heartchamber. The placement of an aortic valve prosthesis is complicated bythe joining of coronary arteries to the aorta near the valve. Therefore,if the prosthesis is not positioned properly, a commissure support canblock or partially block a coronary artery. Diseased heart valves canacquire a tapered shape in which the sinotubular junction end is dilatedto a larger diameter than the annulus end.

[0041] Proper positioning of the valve prosthesis for implantationrequires correct placement of the base or annulus end, to ensure properorientation of the commissure supports. Blood flow is generally from theannulus end (inflow edge) and out through the sinotubular junction end(outflow edge). While suturing the prosthesis at the edge of the base isnot particularly difficult, care must be taken to place the inflowsuture line along a flat plane at the appropriate depth to ensure thatthe prosthesis clears the coronary ostia, and so that the prosthesisfunctions properly. If the inflow edge of the prosthesis is alsoscalloped, similar care must be taken in suturing this type of inflowedge. Suturing the outflow edge, i.e., the sinotubular junction end, ofthe valve along the scallops and the commissure supports, is timeconsuming to complete while maintaining the proper position of theprosthesis.

[0042] The tools described herein have the general shape of the outersurface of an aortic valve prosthesis. However, the tool does not haveto be filled in around the circumference or in the middle as long as thetop and bottom edges provide the desired outline of the prosthesisconfiguration. Therefore, a surgeon can position the sizer/marker in thesame way as the actual prosthesis. More accurate size measurements canbe performed since the tool has the same exterior shape as theprosthesis. Furthermore, in marking embodiments, marks to aid withsuture placement can be made while the surgeon can closely examine theproper placement of the prosthesis without starting the suturing processitself.

[0043] In alternative embodiments, the tools described herein can havethe general shape of the outer surface of a diseased heart valve. Adiseased heart valve generally is tapered outward from the annulus endto the sinotubular junction end. In other words, the valve has a smallerdiameter at the annulus end than at the sinotubular junction end. Sincethe diseased valve generally is tapered, the use of a marker/sizer thatis similarly tapered can produce markings that correspond more closelywith the desired attachment sites of the heart valve prosthesis.Similarly, sizing with a sizer/marker with a tapered shape results in amore accurate determination of size. Generally, if proper measurementswere obtained, implantation of a stented valve prosthesis corrects, atleast to some degree, the deformation at the site of the valve. Also,during valve implantation suturing or other techniques can be used todraw in dilated tissue.

[0044] To perform the sizing, a plurality of sizing tools are used. Byvisual observation, the surgeon can make an initial estimate of theproper size. Then, using the estimate as a guide, several sizing toolscan be sequentially placed into position in the aorta to obtain anaccurate determination of the proper prosthetic size. In preferredembodiments, a set of sizing tools corresponds on a one-to-one basis tothe sizes of the available prostheses. The sizing tools are preferablyreusable with appropriate sterilization between uses.

[0045] The tools also preferably perform a marking function. A properlysized tool in position within the aorta can be used to mark the aorta toguide subsequent attachment of the prosthesis with suture or otherfasteners, such as staples. The markings on the aortic wall can indicatethe entire surface of the prosthesis, an outline of the prosthesis, thelocations of specific suture placement or several reference markings.

[0046] In particular, marking can be performed at appropriate locationsof the aorta wall with a marking fluid, such as an ink or dye, with atemperature change, such as heat or cold, or with propagated energy,such as electromagnetic radiation, that heats the aortic wall. Themarking function can be integral with the sizer in which thesizer/marker emits a marking fluid or transfers energy. Alternatively,the sizer can include position indicators, such as notches, while theactual markings are performed with a separate tool with the guidance ofthe position indicators. In addition, sutures themselves may be used toindicate valve placement. In that case the position indicating notchescould be used to guide suture needle placement for stay sutures.

[0047] By using the sizers, the risk of inadvertently using an improperprosthesis size can be reduced. Also, this ability to properly size theprosthesis prior to insertion of an actual prosthesis can providegreater uniformity and speed of implantation to the procedure since theprosthesis placed within the aorta will have the correct size. Thesizer/marker tool can be particularly useful in the training of surgeonsin the proper implantation of stentless aortic heart valve prostheses.Due to the additional effort required in the implantation of stentlessaortic heart valve prostheses, the procedure can be opened up to agreater number of physicians by increasing their confidence in reliablyplacing the prosthesis in the proper orientation.

[0048] Sizer/Marking Tool

[0049] The sizer/marker tool generally involves a prosthesis templateand a handle extending from the template. The template serves as a sizerto determine the proper annular size and/or the proper sinotubularjunction size of the prosthesis, or as a guide for positioning theprosthesis within the annulus. A separate sizer can be used for directlymeasuring the size of the sinotubular junction and/or the annulus. Thehandle extends from the template to provide for gripping the templatewhen the template is positioned within the aorta. The sizer/marker canbe provided with appropriate structure to supply a marking function, asdescribed further below.

[0050] Referring to FIG. 1, a sizer/marker 100 is depicted within anaorta 102. Aorta 102 is shown as transparent for illustrative purposesto provide a view of sizer/marker 100 within aorta 102. Sizer/marker 100includes a prosthesis template 104 and a handle 106. Prosthesis template104 is positioned within aorta 102 to avoid blockage of openings tocoronary arteries 108, 110.

[0051] An embodiment of a sizer/marker is shown in FIG. 2. Sizer/marker120 includes a prosthesis template 122 and a handle 124. Template 122includes a generally annular base 126 and three posts 128, 130, 132 thatsimulate commissure supports of a native valve. In preferredembodiments, template 122 includes three posts extending upward from thebase corresponding to a prosthetic valve with three leaflets, althoughdifferent numbers of posts, such as two, can be used for a prosthesiswith different numbers of leaflets. Posts 128, 130, 132 are positionedbetween scalloped sections 134. The preferred structure for theprosthesis template contrasts with the outer structure of a stentedaortic tissue valve that has small scalloped flange extending bothoutwardly and upwardly from a cylindrical section or a sizer that justmeasures the diameter of the valve annulus. Using the improved sizers,sizing off the ostia yields an inflow edge plane for prosthesisplacement, which cannot be obtained just by measuring the annulus.

[0052] Handle 124 preferably includes a rigid or malleable shaft 140 anda grip 142. Shaft 140 provides for some flexibility when placingtemplate 122 at the proper location within the aorta. Grip 142 can haveany convenient shape for gripping. Grip 142 can include a button 144 orother suitable structure for implementing marking when the sizer/markeris properly positioned within the aorta. If necessary, grip 142 can beconnected to an external power supply or the like. Also, grip 142 caninclude a reservoir of marking fluid or other compositions useful formarking, as described further below.

[0053] Handle 124 is attached to template 122 at mount 144. A variety ofstructures can be used for mount 144. For example, mount 144 can be aledge or extension located along the inside wall of template 122, asshown in FIG. 2. Alternatively, mount 144 can position extension orshaft 140 at or near the center of template 122, as described below in,for instance, FIGS. 6 and 10. Alternatively, handle 124 may includeanother extended shaft extending in the opposite direction, in which asecond template with a different size is attached to the second extendedshaft. In this alternative embodiment, handle 124 has two templates onopposite ends of the handle, such that the surgeon can easily selectbetween the two sizes of templates. Mount 144 can be designed for thepermanent attachment of handle 124 to template 122 or for the releasableattachment, such that the handle can be used with other sizer/markers.Releasable attachment can be accomplished with a variety of fasteners146, such as a screw type attachment 148 (FIG. 1), a bayonet attachmentwith a compression spring, a snap-fit or other conventional attachmentmechanisms. Permanent attachment of the handle can be accomplished, forexample, by gluing or welding the shaft 140 of handle 124, or by formingthe base around the handle.

[0054] The prosthesis template 122 simulates the size and shape from aside view of an aortic heart valve prosthesis, especially abioprosthetic heart valve. An embodiment of a stentless, tissue heartvalve prosthesis is shown in FIG. 3. Heart valve prosthesis 160 includesa harvested tissue valve 162, such as a crosslinked porcine valve.Prosthesis 160 can further include a fabric cover 164. Valve 162 hasthree leaflets 166, 168, 170 that meet at coaptation surfaces 172. Agenerally annular base 174 and three commissure supports 176, 178, 180support the leaflets. When viewed from the side, the spaces betweencommissure supports 176, 178, 180 form three scallops 182 along the topedge of the prosthesis. Lower edge 184 of prosthesis 160 is the inflowend, and upper edge 186 is the outflow end. In this embodiment, loweredge 184 is generally flat, in contrast with the scalloped upper edge186 of the prosthesis. Markings 188 can be placed along the lower edge184 to assist with placement of the valve.

[0055] Posts 128, 130, 132 shown in FIG. 2 simulate commissure supports176, 178, 180 of prosthesis 160 in FIG. 3. Thus, in preferredembodiments, prosthesis template 122 would have a circumference and sizeand shape of base 126, posts 128, 130, 132, and scallops 134 as acorresponding prosthesis 160. Prosthesis template 122 preferably isformed from a substantially rigid material that will hold its shape whenin position. Suitable materials include, for example, biocompatiblemetal, such as stainless steel or titanium, or polymers, such aspolysulfones, polycarbonates, or acetal.

[0056] The aortic heart valve prosthesis shown in FIG. 3 has a generallycylindrical profile with a flat lower edge and a scalloped upper edge.In alternative template embodiments, the sizer/marker has a curved,non-cylindrical outer surface 190, as shown in FIG. 4A. In addition, thelower, inflow edge can have scallops 192, as shown in FIG. 4B. Thetemplate of the marker/sizer generally has the overall shape of thecorresponding prosthesis, whether or not the profile is cylindrical.

[0057] In another alternative template embodiment, sizer/marker 194 hasa tapered shape, as shown in FIG. 5. Sizer/marker 194 more closelyresembles the shape of a diseased heart valve or the shape of the regionafter a diseased heart valve is removed. Sizer/marker 194 is able to befitted into the heart as a visualization guide or for sizing and markingmore easily than a non-tapered sizer/marker.

[0058] Sizer/marker 194 specifically can include a small taper outwardfrom the lower, i.e., inflow or annulus, edge 195 to the upper, i.e.,outflow or sinotubular junction, edge 196 of the prosthesis template. Asa result of the taper, the area of the valve opening at annulus end 195is smaller than the area of the opening at the sinotubular junction end196 in sizer/marker 194. As with other embodiments, tapered sizer/marker194 for aortic valve replacement preferably includes three posts 197,198, 199 extending from outflow edge 196 of the sizer/marker 194.Sizer/marker 194 can include notches 205 and guide channels 207 tofacilitate the use of a separate marker, as described further below. Thetapered prosthesis template may or may not be conical in shape and mayor may not have a diameter that monotonically increases from the annulusend to the sinotubular junction end.

[0059] Generally, the diameter of the sizer/marker at the annulus end201 is less than the diameter 203 of the sizer/marker at the sinotubularjunction end by between about 1 mm and about 5 mm, even more preferablybetween about 1 mm to about 3 mm. The diameter is evaluated using acircle that approximates the opening, i.e., the lumen of a tube fittingsnugly against the sizer/marker, at the inflow edge and at the outflowedge. The diameter for the inflow edge or the outflow edge is evaluatedusing the smallest circle that includes all of the features of thatedge. Specifically, the diameter of the opening at the annulus edge 195corresponds with the diameter of the smallest circle bounding aprojection of the annulus edge onto a planar surface derived as a planeon which annulus end 195 of sizer/marker 194 would rest. Thus, thediameter is well defined even if the inflow edge is scalloped or hassome other uneven shape. The diameter of the opening at the sinotubularjunction end 196 similarly can be obtained as the diameter of thesmallest circle bounding a projection of the sinotubular junction endonto a plane on which the sinotubular junction end 196 would rest.

[0060] Heart valve prostheses are available in a suitable range of sizesto obtain a proper fit in a patient. Generally, sizer/markers come incorresponding sizes such that once the proper sized tool is identified,the corresponding prosthesis can be selected for implantation. In someembodiments, the prosthesis templates have diameters from about 13 mm toabout 39 mm and in other embodiments from about 17 mm to about 31 mm.For example, for the Toronto SPV® aortic valve prostheses available fromSt. Jude Medical, Inc., the prostheses are commercially available withdiameters of 19 mm, 21 mm, 23 mm, 25 mm, 27 mm and 29 mm.

[0061] Using sizer/marker tools, generally the annulus end and thesinotubular junction end are sized simultaneously. The size at thesinotubular junction end is preferably used to select the appropriatelysized prosthetic valve. A sizer/marker having a tapered shape can moreaccurately determine the appropriate prosthetic valve size and/or themarking sites indicating points for prosthesis attachment. A non-taperedsizer/marker that fits into the annulus end may be smaller than thevalve prosthesis that is appropriate for implantation. This could leadto markings, particularly at the sinotubular junction end, that mightnot optimally correspond to the desired attachment sites of the selectedvalve prosthesis.

[0062] In preferred embodiments, the sizer/marker tool also performs amarking function. The sizer/marker can mark the aorta by contacting thetissue of the aorta with a suitable composition, temperature change orpropagating energy field at desired locations to cause a visible mark,as described further below. In alternative embodiments, the sizer/markerincludes notches or other suitable position indicators such that aseparate marker or suture can be used to mark the tissue by positioningthe marker with the assistance of the position indicator. Since thesizer/marker with position indicator provides the desired positioning,the separate marker can interact with the position indicators to providethe mark at the desired location or at other locations desired by thesurgeon. The separate marker can similarly mark the aorta with acomposition, temperature change or propagating energy. The handle of thesizer/marker or separate marker generally includes a suitable trigger orother actuator to initiate the marking once the marker is at the correctposition.

[0063] For embodiments based on marking fluids, the prosthesis templatecomponent of the sizer/marking tool generally contains pores or openingsat desired locations to mark the tissue when the tool is properlypositioned. In addition, a reservoir of the fluid can be in the handleor within the prosthesis template itself.

[0064] For temperature changes, either cold or hot temperatures can beused to create a color change in the tissue. The temperature change canbe created using a fluid with a suitable temperature or by inducing atemperature change at the surface of the marker. In embodiments based onenergy propagation, the prosthesis template generally supportstransducers that propagate the energy toward the desired locations.

[0065] An embodiment of a sizer/marker for the delivery of an ink, dyeor other marking fluid is shown in FIG. 6. Sizer/marker 200 includes aprosthesis template 202 and a handle 204. Template 202 includes pores206 in its outer surface. The number and location of the pores areselected to leave desired markings on the aorta. In particular, thepores can outline the prosthesis, for instance, by continuous or brokenlines, indicate positions for specific suture placement or provideseveral reference markings. In the embodiment shown in FIG. 6, a row ofpores is located near the inflow edge of the template 202 and a secondrow of pores is located near the outflow edge along the posts and thescallops. Pores with these locations approximately outline the positionof the prosthesis against the aorta.

[0066] Handle 204 includes a tubular section 208, a plunger 210 and anextension 212. Tubular section 208 includes a reservoir 214 of markingfluid. Tubular section 208 has a tapered section 216 that connects withextension 212, although section 216 could be other shapes. Plunger 210includes a grip 226, shaft 228 and plug 230. Grip 226 can be used tomove the position of plug 230 to push fluid from reservoir 214. Plug 230generally has an elastic edge 232 to facilitate movement of plug 230without losing a liquid tight seal. Ridges or stops 233 can be locatedwithin tubular section 208 to stop plunger 210 when sufficient fluid hasbeen dispensed. Alternatively, tubular section 208 can include volumemarking to indicate the volume of fluid or a specific amount of fluidrequired.

[0067]FIG. 7 contains a fragmentary view of the handle 204 with template202 removed. Extension 212 has a main section 234 and three branches236, 238, 240, although the number of branches may vary. A channel 242extends through section 234 and branches 236, 238, 240 such thatopenings 244 at the ends of branches 236, 238, 240 are in fluidcommunication with reservoir 214.

[0068] Referring to FIGS. 6 and 8, template 202 includes three posts250, 252, 254. Template 202 with an outer surface removed is shown inFIG. 8. Template 202 includes a series of channels 256 that lead topores 206 (FIG. 6). As shown in FIG. 8, channels 256 include connectingchannels 258 that are not connected to pores but connect other channelswith each other.

[0069] Openings 244 of branches 236, 238, 240 of FIG. 7 are connectedwith channels 256 of FIG. 8 in sizer/marker 200. Thus, when grip 226 isdepressed, plug 230 pushes liquid from reservoir 214 through extension212 into channels 256 and out from pores 206. Since template 202 shouldbe positioned snugly against the aorta when marking fluid is released, asmall amount of fluid released from the pores should leave localizedmarks at the location of the pores. Wicking needles, a felt tip 259(insert of FIG. 6), jets or other similar mechanism could be located inpores 206 to direct and localize the marking fluid.

[0070] The marking fluid can be an ink, dye or the like. The markingfluid does not have to be permanent, as long as the mark lastssufficiently long to complete the implantation process. Suitable dyesare biocompatible. Preferred dyes include, for example, methylene blue(Faulding Pharmaceuticals), indigo carmine (Hope Pharmaceuticals),Lymphazurin 1% (U.S. Surgical Corp.), Evan's blue, and commerciallyavailable cardiac dyes.

[0071] An alternative embodiment of a sizer/marker is shown in FIG. 9.Sizer/marker 260 is similar to the embodiment in FIGS. 6-8, except thatsizer/marker 260 includes a tubular section 262 sealed from the ambientenvironment. Tubular section 262 further includes air channels 264separated from liquid reservoir 266 by plug 268. Air channels 264 are influid connection with a distinct set of holes 270 in the exteriorsurface of prosthesis template 272 through extender 274. Template 272includes a set of air channels separate from the fluid channels. Whenplunger 276 is depressed, the motion of plug 268 forces marking liquidfrom reservoir 266 through marking holes 278 in template 272 andprovides suction at air holes 270 due to reduced pressure in tubularsection 262. Suction at air holes 270 holds template 272 in place whilethe marking fluid is being deposited. The suction available in thesurgical room can be used for suction instead of the plunger byconnecting air channel 264 with the suction. Other sizer/markerembodiments can also be adapted with suction.

[0072] Another embodiment of a sizer/marker based on the use of amarking fluid is shown in FIG. 10. Sizer/marker 290 is similar tosizer/marker 200 shown in FIGS. 4-6 except that pores 206 (FIG. 6) arereplaced with needles 292 (FIG. 10). Needles 292 are in a sealedplacement with pores similar to holes 206 of FIG. 6. Needles 292 includedye or other marking fluid within a small capillary. When the plunger isdepressed, movement of the fluid pushes needles 292 outward such thatneedles 292 extend further from their pores and into the tissue of theaorta. If the plunger is then pulled up, needles 292 withdraw into theirpores, and the sizer/marker can be removed. Inserting needles 292 intothe aorta wall deposits some of the marking fluid to mark the wall ofthe aorta below the surface as a tattoo.

[0073] As noted above, a low temperature surface can be used to mark theaortic tissue. In particular, cooling fluid can be circulated adjacentthe tissue to be marked to freeze the tissue and cause a visiblediscoloration. If association with the cooling fluid is not maintainedfor too long of a period of time or at too low of a temperature, thetissue will not be frozen to the point of causing damage to the tissue.Then, the tissue will recover after a brief period of time. The colorchange of the frozen tissue can last long enough to complete theattachment of the prosthesis. Suitable cooling fluids include, forexample, refrigerants, such as, CO₂ and freon, and cryogenic fluids,such as, liquid nitrogen, liquid oxygen, liquid helium, and liquidargon.

[0074] A sizer/marker 300 for marking with a cooling fluid is shown inFIG. 11. Sizer/marker 300 includes a handle 302 and prosthesis template306. Handle 302 includes a pressure vessel 308 of cooling fluids and anextension 310. Pressure vessel 308 contains a cooling fluid undersufficient pressure to maintain it in the liquid state. Sufficient fluidshould be used to obtain a desired temperature drop upon expansion ofthe fluid. A pressure valve 312 controls the flow of cooling fluid fromvessel 308. Valve 312 includes a stopcock 314 with a hole 316. Knob 318can be used to open and close vessel 308 by rotating stopcock 314. Therotated configuration of stopcock 314 is shown in the cross sectionalview in the insert. When open, vessel 308 expands rapidly into channel320, which extends from handle 302 into extension 310. Extension 310includes a liquid channel 322 which can be connected to template 306using arms similar to those shown in FIG. 7. Handle 302 further includesan air channel 323, which provides for venting during flow of coolingfluid. Handle 302 preferably is open to the outside atmosphere.

[0075] Template 306 includes liquid channels 330 for cooling fluidwithin template 306 or on the surface of template 306. Liquid channels330 are located at positions along template 306 corresponding to desiredmarking locations for attachment and positioning of the prosthesis.Generally, the surfaces of channels 330 are sufficiently thermalconducting to mark the tissue contacting the surface of the channels.Portions of liquid channels 330 can be insulating to control theresulting markings. Air channel 323 connects to template 306 with ventarms 326. Vent arms 326 include channels that are in fluid communicationwith liquid channels 330 as well as air channel 323.

[0076] After sizer/marker 300 is properly positioned, knob 314 is turnedto release cooling fluid. The cooling fluid expands rapidly intoextension 310 and then into template 306, thereby cooling liquidchannels 330. Vessel 308 can be left open while sizer/marker 300 isremoved.

[0077] A sizer/marker for marking by heating or energy propagation isshown in FIG. 12. These embodiments result in a tissue that isdiscolored over the marked regions. In this embodiment, prosthesistemplate includes a transducer 350. The handle is shown in phantomlines. The template can just include the transducer, or the transducercan be placed over or around an electrically nonconducting support thatprovides additional structure to the template. If the template justincludes the transducer, the transducer preferably provides an outlineof the outer shape of the corresponding prosthesis. Transducer 350includes a scalloped section 352 that generally follows the outflow edgeof the prosthesis, a ring section 354 that approximately corresponds tothe inflow edge of the prosthesis, and connecting supports 356, 358, 360between the scalloped section 352 and the ring section 354. The shape ofthe transducer can be altered to provide a desired set of markings.

[0078] The handle generally will include a switch 362, which iscontrolled by a knob 364. Switch 362 is connected to a power supply 366.Power supply 366 can be, for example, a battery with or without acapacitor, a transformer or a connection to exterior line voltage. Anoptional oscillator 368 can be connected to switch 362, but oscillator368 need not be in the handle. Oscillator 368 can be used to generateradio frequency or other frequency alternating currents. Wires 370connect the components in the handle with transducer 350.

[0079] Transducer 350 can be a resistance heater. In these embodiments,scalloped section 352 and ring section 354 are formed from electricallyresistive material that heats up when current flows through them.Generally, current is flowed for, at least, several seconds to providethe desired amount of heating. Suitable resistive material includesalloys of chromium, aluminum or both. To obtain appropriate current flowthrough the desired elements, support 356 can be made from electricallyconducting material while supports 358 and 360 are made fromelectrically insulating material, such as ceramic materials. Wires 370make electrical contact at connections 372, 374. In these embodiments,direct current or oscillating current can be used.

[0080] For radio frequency heating or other electromagnetic radiationbased heating, a suitable oscillator 368 is used. The transducer 350 isthen a transmitter that propagates electromagnetic energy. Supports 356,358, 360 can all be electrically insulating. Then, scalloped section 352and ring section 354 act as counter electrodes for the transmitter.

[0081] In one embodiment, the sizer/marker could be connected to asurgical cautery unit, which generates an electrical potential. Thesurgeon then marks the tissue with an electrical arc discharged frommetal conductors on the template of the sizer/marker.

[0082] In alternative embodiments, the prosthesis template component ofthe sizer/marker can include position indicators rather than markingmeans. Thus, the template provides the capability to mark the aorta atdesired locations without actually doing the marking. A separate markeris designed to interface with the position indicators. In other words,the marker tip fits into the position indicators to provide an accuratemark at the locations specified by the position indicators or at otherlocations desired by the surgeon.

[0083] An embodiment of a prosthesis template with position indicatorsis depicted in FIG. 13. Template 380 has a generally cylindrical basesection 382 with three posts 384, 386, 388 extending from base 382. Ahandle would be appropriately attached to template 380, as discussedabove. Position indicators 390 are indentations located, for example, ator near maxima of the posts, at the minima of the scalloped sections inbetween the posts and at three positions along the bottom or inflow edgeof base 382, as shown in FIG. 13.

[0084] A suitable marker 400 for use with template 380 is depicted inFIG. 14. Marker 400 includes a handle 402 and a tip 404. Handle 402includes a reservoir 406 that holds marking fluid. Reservoir 406 isconnected to a channel 408 that leads to a capillary within tip 404. Tip404 fits within position indicators 390 shown in FIG. 13, such thatcarefully placed marks can be made or sutures can be placed with thetemplate in position within the aorta.

[0085] Alternatively, a hooked implement, such as a blunt ended nervehook or the like, can be dipped into a marking fluid, such as ink, toperform the marking. In other alternative embodiments, tip 404 isslotted like a nib or has a felt tip like a marker, or some other typeof mechanism.

[0086] An alternative embodiment of a prosthesis template with positionindicators is shown in FIGS. 15-19 for use with aortic xenograftbioprostheses, such as Toronto SPV® heart valve prostheses sold by St.Jude Medical, Inc. Prosthesis template 450 has a slight asymmetrycorresponding to the general structure of a porcine valve prosthesis toassist with positioning and marking. Prosthesis template 450 includes aprotrusion 452 with a handle connector hole 454 for attaching a handle,for example with a screw attachment, a bayonet attachment or gluing inplace.

[0087] Template 450 includes a base 460 and three posts 462, 464, 466.The centers of posts 462, 464, 466 may be equally spaced at 120°, but itis preferred to place them asymmetrically at unequal angles that moreclosely match the anatomical spacing of an aortic porcine heart valve,such as used in the Toronto SPV® valves. Such spacing is approximately110° between 464 and 466, and 115° between 464 and 462.

[0088] When the corresponding sizer/marker is properly located, the leftcoronary sinus and left coronary artery are between posts 464, 466, theright coronary sinus and right coronary artery are between posts 462,464, and the noncoronary sinus is between posts 462, 466. Alternatively,the left coronary sinus and left coronary artery could be between two ofthe other posts. The tops of posts 462, 464, 466 may include notchessimilar to notches 390 in FIG. 13 to guide marking or may be left smoothso that marks or sutures may be placed at any location. The height ofeach post 462, 464, 466 may be the same, or preferably the heights maybe different from each other to approximately match the height ofcorresponding commissure supports of the bioprosthetic valves, forexample the Toronto SPV® valves, such as shown in FIGS. 20 and 21. Asshown in FIGS. 20, 21, posts 492, 494, 496 of template 498 havedifferent heights from inflow edge 500.

[0089] To guide the placement of marks at the bottom or inflow edge oftemplate 450, each post 462, 464, 466 includes guide channels 474, 476,478, as shown in FIG. 16. Only channel 476 lines up with the center ofpost 464 to match markings on the Toronto SPV® valve. The angles of theposts 462, 464, 466 are not the same as the angles of notches 480, 482,484, since posts follow the naturally occurring leaflet coaptation (172in FIG. 3), and the notches align to markings 188 in FIG. 3. Channels474, 476, 478 may extend completely from approximately the top to thebottom of the posts of template 450, as shown in FIGS. 15, 17 and 18, orchannels 502, 503 can extend partially from top to the bottom of theposts of template 504, as shown in FIGS. 21 and 22. Channels 474, 476,478 are spaced apart approximately 120 degrees relative to a centerline. Channels 474, 476, 478 lead to three notches 480, 482, 484 alonginflow edge 486 of template 450, as shown in FIGS. 15 and 17-19.

[0090] Thus, using the tops, optionally including notches 390, of posts462, 464, 466 and notches 480, 482, 484, six marks can be made with, forinstance, marker 404 or sutures. Three of the marks correspond to thetops of the commissure supports of the prosthesis, and three of themarks correspond to three suture guide markings 188 (FIG. 3) found alongthe inflow edge of the Toronto SPV® valves spaced at approximately 120degrees relative to each other. These six visual reference points can beused to position the prosthesis.

[0091] An alternative embodiment of a template with position indicatorsis shown in FIG. 23. Template 510 has curved outer surfaces 512 thatmatch the aortic sinuses of the prosthetic valve. One marking hole 514through the side of the template is shown in FIG. 23. A channel 516leading to marking hole 514 is shown in phantom lines. In preferredembodiments, two additional marking holes and channels would be locatedat approximately 120° from the marking hole shown. Template 510 includesa subannular cylindrical sizing section 518 extending below the markingholes for sizing the heart valve annulus.

[0092] Use of Sizer/Marking Tool

[0093] The sizer/markers described herein can be used to facilitate theselection and implantation of an aortic heart valve prosthesis. Sizingand marking are performed following the removal of the damaged ordiseased natural heart valve prior to implantation of the replacementheart valve prosthesis. The use of the sizer/marker can improve theconsistency of the replacement procedure, decrease the complexity of theattachment of the prosthesis and reduce the implantation time.

[0094] As with any open heart procedure, the process is initiated byplacing the patient on appropriate life support and by opening the chestcavity to make the heart accessible. Then, a transverse aortotomy isperformed to make the natural valve accessible through the aorta. Thepreferred location for opening the aorta may depend on precise structureof the prosthesis. For a Toronto SPV® prosthesis, the aorta is cut about1 cm above the sinotubular junction. The damaged or diseased naturalvalve leaflets are removed, preferably along with the calcium andcalcific debris.

[0095] The aortic valve prosthesis generally is placed between theaortic annulus, a slight narrowing where the aorta joins the heart, andthe sinotubular junction, a slight narrowing of the aorta just downstream from the coronary arteries. However, the prosthesis can extendbeyond the aortic annulus and/or the sinotubular junction. If desired,an initial measurement can be made of the diameter of the aortic annulusand/or the sinotubular junction. With or without making initialmeasurements, a sizer is selected and inserted, to the extent possible,into the position such that the prosthesis template of the sizer is inthe correct position corresponding to the prosthesis. The surgeon canthen evaluate the appropriateness of the size of the sizer tool.Preferably, a tapered prosthesis template, as described above, is usedand is of the appropriate size at both the annulus end and thesinotubular junction end. At the discretion of the surgeon, the surgeoncan similarly place one or more additional sizers into position toevaluate aortic size. After positioning one or more sizers within theaorta, the surgeon selects a sizer that has a desired size relative tothe patient's aorta, particularly at the sinotubular junction end. Then,a corresponding prosthesis with the same size can be obtained forimplantation.

[0096] If marking of the aorta is also desired, the marking is donefollowing completion of the size selection. The sizer/marker with theselected size is inserted into position within the patient's aorta. Theorientation of the sizer/marker is properly adjusted prior to themarking. Once the appropriate position and orientation of thesizer/marker is obtained, the marking is performed. The marking can bedone by pressing a knob, button, switch or other actuator on the handleof the sizer/marker to initiate the marking, as described above withrespect to particular embodiments, and/or using a separate marker thatis placed at particular position indicators on the prosthesis templateof the sizer/marker. Marks are placed at appropriate locations relativeto the prosthesis template to assist with implantation of theprosthesis.

[0097] The prosthesis with the selected size is then implanted. Ifmarkings have been made, these can be used to orient the prosthesis.Alternatively, the prosthesis can be oriented by eye. In someembodiments, the position of the markings specifically guides theplacement of sutures or other fasteners, such as staples.

[0098] In the preferred embodiment, the sizer/marker posts and scallopsare oriented to assure clearance of the coronary ostia. For example,marking at the inflow edge can result in three 120 degree spaced dyemarks aligned in a plane slightly below the patient's excised aorticleaflets. Three sutures may then be placed using a vertical interruptedtechnique such that the distal end of each suture exits from the tissueat each mark. The distal suture ends are then passed through the inflowedge of the valve prosthesis at their corresponding 120 degree spacedmarkings. The sequence of suture routing, number of sutures, and methodof suture placement may be at the discretion of the surgeon.

[0099] Simple interrupted suture are then placed in equal numbersbetween the three 120 degree sutures. A total of approximately 16 to 18equally spaced, simple vertical interrupted sutures define the locationof the inflow edge of the valve.

[0100] The sizer/marker 120 degree inflow marks locate the depth of theinflow suture plane. This assures that the prosthetic valve is implanteddeep enough to clear the coronary ostia. The radial orientation of thethree marks leads to the proper radial orientation of the prostheticvalve's commissure supports. During suturing of the prosthetic valve'soutflow edge, the dye marks that were placed at the top of thesizer/marker posts guide the radial orientation of the valve commissuresupports. Preferably, the dye marks were placed using a tapered shapetemplate in order to obtain desirable correspondence between the dyemarks and the desired location of the sutures during attachment of theprosthesis.

[0101] In preferred embodiments, the sizer/markers are reusable.Following use of the sizer/markers, all of the sizer/markers used in theprocedure are sterilized prior to their next use. Appropriatesterilization procedures may depend on the materials used to form thesizer marker. Suitable sterilization procedures include, for example,chemical sterilization, radiation sterilization, and heat sterilization.Chemical sterilization can use aldehydes, peroxides or other chemicalsterilants. Radiation sterilization can be based, for example, on anelectron beam, ultraviolet light, gamma rays or other electromagneticradiation. Heat sterilization, for example, can be performed in anautoclave, heated water or the like.

[0102] Distribution and Packaging

[0103] The sizer/markers generally are distributed as a set with atleast one member of the set corresponding in size with the size ofavailable prostheses. Thus, a sizer/marker will be available to evaluatethe size of the annulus of the patient in relation to each availableprosthesis. For convenience, all of the sizer/markers of a set can beplaced within a single container, such as a box with slots for holdingthe sizer/markers. The container can be made to be compatible withradiation or heat sterilization, such that the sizer/markers can besterilized within the container.

[0104] Generally, the sizer/markers are distributed to hospitals and anyother location where valve replacement procedures are performed.Generally, the sizer/marker sets are distributed, such that they areavailable at the medical facility when needed. The sizer/markers can bedistributed along with instructions for proper use along with any otherdesired or required documentation. The sizer/markers can be sterilizedin storage, such that they are immediately ready for use, or they can besterilized immediately prior to each use.

[0105] The embodiments described above are intended to be illustrativeand not limiting. Additional embodiments are within the claims below.Although the present invention has been described with reference topreferred embodiments, workers skilled in the art will recognize thatchanges may be made in form and detail without departing from the spiritand scope of the invention.

What is claimed is:
 1. A tool comprising a prosthesis template, theprosthesis template having an annulus end and a sinotubular junctionend, the prosthesis template further comprising a plurality of postsaround the circumference extending toward the sinotubular junction end,wherein the diameter at the annulus end is less than the diameter at thesinotubular junction end.
 2. The tool of claim 1 further comprising ahandle extending from the prosthesis template.
 3. The tool of claim 1wherein the annulus end has a diameter less than the diameter of thesinotubular junction end by from about 1 millimeter (mm) to about 5 mm.4. The tool of claim 1 wherein the annulus end has a diameter less thanthe diameter of the sinotubular junction end by from about 1 millimeter(mm) to about 3 mm.
 5. The tool of claim 1 wherein the posts haveunequal heights.
 6. The tool of claim 1 wherein the plurality of postsare three posts.
 7. The tool of claim 6 wherein the three posts are notsymmetrically oriented around the prosthesis template.
 8. The tool ofclaim 1 wherein the posts are connected by scallops.
 9. A method forguiding the attachment of an aortic heart valve prosthesis, the methodcomprising inserting a tool of claim 1 into the aorta to visualize thepositioning of the prosthesis.
 10. A tissue marking device comprising aprosthesis template having an annulus end and a sinotubular junctionend, wherein a diameter of the annulus end is less than a diameter ofthe sinotubular junction end and a marker having a marking tip thatinterfaces with notches of the prosthesis template, wherein the markeris separately positionable from the prosthesis template.
 11. The tissuemarking device of claim 10 further comprising a handle attached to theprosthesis template.
 12. The tissue marking device of claim 10 whereinthree posts are located at the sinotubular junction end.
 13. The tissuemarking device of claim 12 wherein the three posts have equal height.14. The tissue marking device of claim 12 wherein the three posts havean unequal height.
 15. The tissue marking device of claim 10 wherein theprosthesis template further includes channels leading to the notches.16. The tissue marking device of claim 10 wherein the diameter of theannulus end is less than the diameter of the sinotubular junction end byabout 1 mm to about 5 mm.
 17. The tissue marking device of claim 19wherein the three posts are not symmetrically positioned around thetemplate.
 18. A tissue marking device comprising a prosthesis templatehaving an annulus end and a sinotubular junction end, wherein a diameterof the annulus end is less than a diameter of the sinotubular junctionend, the prosthesis template comprising a marking element configured tomark tissue at particular positions relative to the prosthesis template.19. The tissue marking device of claim 18, further comprising a handleand wherein the marking element comprises pores on the outer surface ofthe prosthesis template and wherein the handle comprises a reservoir anda plunger forming a surface of the reservoir.
 20. The tissue markingdevice of claim 18 wherein three posts are located at the sinotubularjunction end.